Around Capitol Hill, there's nothing quite so common as the friendly legislator plying colleagues with promotional gifts of peanuts, raisins, orange juice and other home-state goodies, so no one looked twice when Rep. George Miller (D-Calif.) came toting boxes of navel oranges.

But George Miller, not your typical booster, wasn't promoting navel oranges in the House restaurant that day in May. He was trying to make the point that those lovely oranges and millions more like them couldn't be sold because of federal regulations.

Miller didn't say so, but he just as easily could have brought quantities of dates, prunes, milk, raisins, avocados, potatoes, peaches or several dozen other fruits and vegetables. Like the navel orange, their distribution to the American consumer is tightly regulated by Uncle Sam.

The device that makes this possible is called the federal marketing order. Farmers and the Department of Argiculture like to call the marketing order a cornerstone of a system that keeps high quality produce flowing steadily to the consumer. What they don't say is that it also keeps prices up.

Miller and others on his side -- including a growing number of farmers -- see the marketing order as a mockery of the free-market philosophy that the Reagan administration and conservative farm groups espouse with such vigor. The more severe of the critics say the marketing order is a license for price fixing.

For its part, the administration has included a review of marketing orders under its broader look at federal regulatory programs that are too expensive or inefficient.

News stories in recent months have spotlighted this little-understood strand in the great web of federal regulation of agriculture and set consumer tempers aboil.

In March, for instance, millions of navel oranges bearing the Sunkist label were fed to cattle in California or left to rot in the sun because their sale would have violated the marketing order that allows only so many oranges to go to market each week. A General Accounting Office study released by Miller Friday confirmed that at least 46 percent of this year's navel oranges crop was withheld from consumers by the marketing order.

Meanwhile, in April, peach growers in California bulldozed 2,000 acres of orchards to prevent an excess of cling peaches from flooding the market and forcing prices down. A marketing order strictly controls the number of peaches that farmers may sell to processors.

What is going on here, in a time of increasing strains on the American food producing system, when federally subsidized irrigation water helps western farmers bolster their yields, when the government claims to be taking every possible step to keep consumer prices down?

Under laws passed during the Depression, growers and processors of certain fruits and vegetables, as well as dairymen, were authorized to band together under marketing orders to control the flow of produce to market and improve their profits.

There are now 48 of these marketing orders and agreements, affecting about 140,000 farmers in 30 states with an annual production of $5.2 billion. In some cases, according to a USDA study in 1975, these arrangements caused what the experts called "price enhancement" -- meaning, higher prices -- for oranges, lemons, prunes, tart cherries, raisins, hops and Florida celery, among other commodities. A potential for increasing prices was found for others.

A later USDA study, prepared by agricultural economist Edward V. Jesse, now at the University of Wisconsin-Madison, looked at social welfare implications of the marketing arrangements. Jesse found some fault with the orders, from a consumer viewpoint, but concluded that they could neither be condemned nor justified for their social impacts.

Now, spurred in part by the publicity about this year's navel orange situation, the administration is taking a new look at the marketing order system as part of its review of federal regulatory actions.

A USDA task force, headed by departmental economist Richard Heifner and including Jesse, is reviewing the marketing order program with an eye toward its effects on productivity and efficiency.

Meanwhile, on Capitol Hill, George Miller is trying to persuade fellow navel orange lovers to help pass his bill that would give consumers a larger role on the marketing order boards that determine how much produce goes to market.

"The marketing order system is an anachronism . . . . it results in higher prices for consumers and higher profits for growers," Miller said.

A hearing is expected on Miller's bill later this year.